What to Expect During

Sleep studies are painless. Parents can go with their children to a sleep study.

The polysomnogram (PSG), multiple sleep latency test (MSLT), and maintenance of wakefulness test (MWT) are usually done at a sleep center. The room the sleep study is done in may look like a hotel room. A technician makes the room comfortable for you and sets the temperature to your liking.

Most of your contact at the sleep center will be with nurses or technicians. You can ask them any questions that you may have about the sleep study. During a Polysomnogram

Sticky patches called sensors are placed on your scalp, face, chest, limbs, and a finger. While you sleep, these devices record your brain activity, eye movements, heart rate and rhythm, blood pressure, and the amount of oxygen in your blood.

Elastic belts are placed around your chest and abdomen. They measure chest movements and the strength and duration of each exhaled breath.

Wires attached to the sensors transmit the data to a computer in the next room. The wires are very thin and flexible and are bundled together to minimize discomfort. You will be able to roll in any direction.

A technician in another room monitors the recordings as you sleep. He or she fixes any problems with the recordings that occur.

The technician also helps keep you comfortable and disconnects the equipment if you need to go to the bathroom.

When it's time for you to sleep, the room will be dark and quiet.

Polysomnogram

The illustration shows the standard setup for a polysomnogram. In figure A, the patient lies in a bed with sensors attached to the body. In figure B, the polysomnogram recording shows the blood oxygen level, breathing event, and rapid eye movement (REM) sleep stage over time.

The illustration shows the standard setup for a polysomnogram. In figure A, the patient lies in a bed with sensors attached to the body. In figure B, the polysomnogram recording shows the blood oxygen level, breathing event, and rapid eye movement (REM) sleep stage over time.

If you show signs of sleep apnea, you may have a split-night sleep study. During the first half of the night, the technician records your sleep patterns. At the start of the second half of the night, he or she wakes you to fit a continuous positive airway pressure (CPAP) mask over your nose and mouth.

The mask is connected to a small machine that gently blows air through the mask. This creates mild pressure that keeps your airways open while you sleep.

The technician checks how you sleep with the CPAP machine. He or she adjusts the flow of air through the mask to find the setting that's right for you.

At the end of the PSG, the technician helps you out of bed and removes the sensors. If you're having a daytime sleep study, such as an MSLT, some of the sensors may be left on for that test.